US Patent 7588644 Method and apparatus for cleaning pipeline pigs

A method of cleaning pipeline pigs of a material that is to be recycled includes providing a vessel having an interior. A manifold is placed within the vessel interior, the manifold having a plurality of openings. The vessel is filled with a solvent that is capable of dissolving the material to be recycled. The pipeline pig is placed in the vessel and above the manifold. A volume of gas is bubbled into the vessel via the manifold openings. These steps are repeated with multiple pigs in sequence so that the material to be recycled is concentrated over time within the vessel. Thereafter, the material that has accumulated within the vessel is recycled. The solvent is preferably a terpene blend with an ethoxylated alcohol. The material to be recycled is preferably paraffin and/or asphaltene.